This is not critical, but I am curious to learn. Are there any suggestions for speeding up the process to calculate a moving row sum? (Ideally from within R, as opposed to suing C, etc.) Using rollapply on a matrix of 45,000 rows and 400 columns takes 83 minutes.
date() mymatrix <- matrix(data=1:45000, nrow=45000, ncol=400) temp <- t(rollapply(t(mymatrix), width=12, FUN=sum, by.column=T, fill=NA, partial=FALSE, align="left")) date() On Thu, Jun 27, 2013 at 2:41 PM, arun <smartpink...@yahoo.com> wrote: > Hi, > Try: > library(zoo) > > rollapply(t(mymatrix),width=12,FUN=sum,by.column=T,fill=NA,partial=FALSE,align="left") > # [,1] [,2] [,3] [,4] [,5] > #[1,] 342 354 366 378 390 > #[2,] 402 414 426 438 450 > #[3,] 462 474 486 498 510 > #[4,] 522 534 546 558 570 > #[5,] 582 594 606 618 630 > #[6,] 642 654 666 678 690 > #[7,] 702 714 726 738 750 > #[8,] 762 774 786 798 810 > #[9,] 822 834 846 858 870 > #[10,] NA NA NA NA NA > #[11,] NA NA NA NA NA > #[12,] NA NA NA NA NA > #[13,] NA NA NA NA NA > #[14,] NA NA NA NA NA > #[15,] NA NA NA NA NA > #[16,] NA NA NA NA NA > #[17,] NA NA NA NA NA > #[18,] NA NA NA NA NA > #[19,] NA NA NA NA NA > #[20,] NA NA NA NA NA > A.K. > > > > ----- Original Message ----- > From: Anika Masters <anika.mast...@gmail.com> > To: R help <r-help@r-project.org> > Cc: > Sent: Thursday, June 27, 2013 3:00 PM > Subject: [R] using "rollapply" to calculate a moving sum or running sum? > > #using "rollapply" to calculate a moving sum or running sum? > > #I am tryign to use rollapply to calcualte a moving sum? #I tried > rollapply and get the error message > #"Error in seq.default(start.at, NROW(data), by = by) : > # wrong sign in 'by' argument" > > #example: > > mymatrix <- ( matrix(data=1:100, nrow=5, ncol=20) ) > mymatrix_cumsum <- ( matrix(data=NA, nrow=5, ncol=20) ) > w=12 > for(i in 1: (ncol(mymatrix)-w+1) ) { > mymatrix_cumsum[ , i] <- apply(X=mymatrix[, i:(i+w-1)] , MARGIN=1, > FUN=sum, na.rm=T) > } > > #How might I use the "rollapply" function instead? > > rollapply(mymatrix, 12, sum) > > rollapply(data = mymatrix, width = 12, FUN=sum, by.column =T, fill = > NA, partial = FALSE, align = "left" ) > > ______________________________________________ > R-help@r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide http://www.R-project.org/posting-guide.html > and provide commented, minimal, self-contained, reproducible code. > ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.